From cc1780fc42c76c705dd07ea123f1143dc5057630 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Wed, 20 Feb 2019 13:32:11 +0000
Subject: [PATCH] KEYS: user: Align the payload buffer
Git-commit: cc1780fc42c76c705dd07ea123f1143dc5057630
Patch-mainline: v5.0-rc8
References: bsc#1051510

Align the payload of "user" and "logon" keys so that users of the
keyrings service can access it as a struct that requires more than
2-byte alignment.  fscrypt currently does this which results in the read
of fscrypt_key::size being misaligned as it needs 4-byte alignment.

Align to __alignof__(u64) rather than __alignof__(long) since in the
future it's conceivable that people would use structs beginning with
u64, which on some platforms would require more than 'long' alignment.

Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Fixes: 2aa349f6e37c ("[PATCH] Keys: Export user-defined keyring operations")
Fixes: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 include/keys/user-type.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index e098cbe27db5..12babe991594 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -31,7 +31,7 @@
 struct user_key_payload {
 	struct rcu_head	rcu;		/* RCU destructor */
 	unsigned short	datalen;	/* length of this data */
-	char		data[0];	/* actual data */
+	char		data[0] __aligned(__alignof__(u64)); /* actual data */
 };
 
 extern struct key_type key_type_user;
-- 
2.16.4